Room-Temperature Self-Healing Composites with Excellent Strength and Toughness for Anticorrosion Applications

Materials that are mechanically robust and possess room-temperature self-healing capabilities hold significant practical value. This study focuses on the fabrication of room-temperature self-healing polymer composites with outstanding strength and toughness by integrating nanoparticles of 2-ureido4[1H]-pyrimidinone-grafted zinc imidazolate framework-7 (ZIF-7-UPy) into polyurethane. The incorporation of ZIF-7-UPy nanoparticles establishes multivalent hydrogen bonding interactions with the polymer chains, serving as universal physical cross-linkers that notably enhance the mechanical properties of three distinct polyurethane (PU) systems. The resulting composite, polyurethane/2-ureido4[1H]-pyrimidinone-grafted zinc imidazolate framework-7 (PU/ZIF-7-UPy), demonstrates a tensile strength of 48 MPa and a toughness of 272 MJ m^-3. The exceptional reversibility of hydrogen bonds imparts efficient room-temperature self-healing and reprocessability to the composites. The tensile strength of PU/ZIF-7-UPy can be restored to 87% of its original value at room temperature. Notably, the synthesized PU/ZIF-7-UPy composites had excellent anticorrosion properties owing to their ability to autonomously self-healing in acidic environments via the intelligent release of corrosion inhibitor. This work presents a straightforward yet versatile approach for designing multifunctional, mechanically robust materials with room-temperature self-healing capabilities.